Inhibited Surface Diffusion of High-Entropy Nano-Alloys for the Preparation of 3D Nanoporous Graphene with High Amounts of Single Atom Dopants

Nitrogen- and metal-atom-doped graphene are very promising electrocatalysts for many renewable energy conversion reactions such as oxygen reduction/evolution reactions (ORR/OER). To maximize the bifunctional or multifunctional catalytic performance, increasing the doping amount of both nonmetal nitrogen and metals on large-surface-area free-standing 3D porous graphene is very desirable. Herein, we design and prepare 3D bicontinuous nitrogen and noble-metal single atoms/clusters-doped small-pore-size nanoporous graphene by a CVD process using a designed 12-component ultrahigh-entropy nanoporous alloy template, which has greatly inhibited surface diffusion even under high temperatures of 800–1000 °C because of the incorporation of a suitable amount of high-melting-point metals. With a small-pore size of ∼16.7 nm and a high curvature, the 3D nanoporous graphene is able to host/stabilize a high amount of N (5.88 at. %) and metal single atoms/clusters (Au, Pt, and Ir), which are in situ anchored on graphene during the removal of the nanoporous template. As a result, the obtained 3D graphene-based composite exhibits excellent electrocatalytic activities toward both ORR and OER in both alkaline and acidic media. This work demonstrates a scalable and economic route to prepare metal- and nonmetal-codoped 3D graphene with ultrasmall porosity for different electrochemical applications.